Because little is known about the development of lung parenchyma, this article focuses on developmental airway changes. The lung continues to develop throughout most of a person's life. Alterations to bronchi and bronchioli during the distinct phases of early life (ie, human intrauterine development, birth, or infancy) may predispose people to development of airflow limitation later. Both genetic and exogenous factors, such as fetal or neonatal passive exposure to tobacco smoke, viral lower respiratory tract infections, prematurity, or neonatal mechanical ventilation, may influence development [1]. This study investigates to what extent environmental factors and exposures, such as cigarette smoking, affect airway development throughout a lifespan and whether these patterns differ between men and women. The general and sex-specific patterns of fetal, perinatal, and postnatal lung growth and growth patterns in childhood, puberty, and adulthood are described.
